import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class code1 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] dp = new int[n+1];
        dp[0]=dp[1]=1;
        int sum = 2;
        for(int i=2;i<=n;i++) {
            dp[i]+=sum;
            sum+=dp[i];
        }
        System.out.print(dp[n]);
    }
}